yes. though generally the amount that you adjust the primary butterfly for the idle is very small and has little effect on the tps. if your tps is fairly close in voltages i dont think it would be causing the problems u describe. it sounds like map sensor, or maybe something ignition related. is your FPR set up correctly?

First we will have to make sure your basics have been covered. Check all the fuses. Then pull each plug wire and verify you have spark at each one. you are apparently getting fuel, but is it getting too much? pull the plugs and see if both chambers are combusting. look for variations between the front and rear rotor plugs. IE: is one side sooty and black and the other very clean and wet with fuel.

Was the CAS installed correctly, are the wires for it all okay? Is the front injector clip on the front injector.

You might want to check the map sensor anyways. if its still giving off a voltage the stock ecu may not trigger a CEL. at least you can get that out of the way, its fairly easy to test. just need a voltimeter and a mity vac.

These cars can be stuborn and difficult as hell, but when it comes down to it its all just lots of simple components that all need to work together. if you go through each, one at a time eventually you will find your problem.

Since you're running the stock ecu you can also check for stored codes. I dont think they always will trigger a CEL but i could be wrong.

hey, Rotary experiment seven, If I could, id be there today cuz this shit is making me crazy. I did all the mods and followed the rebuild vid. to the T Don't know what else could be causing this.
BUT I BET IT"S SOMETHING REALLY SMALL AND STUPID!!!!! I thought the hardest part would be putting the engine itself back together properly.

THANKS for the prodecure dudemaaanownanrx7. I'll follow you thoughts to the letter and see what comes of it. At this point, I'm desperate.

Almost all of my ignition system and fuel system is aftermarket. I eliminated the fuel dampner and replaced the regulator with one with a dial and gauge and it's set at 40 psi. My coils, well the leading anyway, is fired by an MSd unit to iridium plugs via magnecore wires. It is possible that only one rotor if firing so i'll check that.

so you are running aftermarket injectors as well? If so that will be a problem on the stock computer.

Thats why I asked if you have changed the primaries. (secondaries are not important @ idle)
But with aftermarket, it could possibly be that they have another lag-time. So maybe stock ECU can´t handle it and the injectors may stay open too long for idle. So stalling etc can occur.


Another important thing is, that you should look if the aftermarket injectors are still high impedance injectors or if they are now low impedance injectors, like most of the larger injectors (1600, 1680cc ... etc.) are.

If they are low impedance (not common on stock size(550cc prim and 850cc sec)) you have to put a resistor in row!

If impedance isn´t right too much current is needed 4 the injectors to built up the magnetic field in the injector which is needed to open against the fuel pressure.
And then either the components in the ECU are made for this current (damage to your ECU!) nor the complete circuit design isn´t made for this current so filter effects may cause aditional lag time to built up current->mag. field->open the injector --> so fuel amount doesent fit --> poor idle.

If something here isn´t right, also driving @ different boost / revs can be poorly. Not only idle!


Hopefully it is something really easy!
Because if you have a problem with the injectors... maybe this will coerce you to buy a PFC (or similar) to handle the changes!

greetings Marc


PS: a PFC is not the badest invest @ all in your situation I think, even if you could solve this problem in another way!

n, i apologize for the confusion, The injectors are stock. Both the primaries and the secondaries

With all of your mods I am not surprised you are having problems with a stock ECU. I think you need to go to an aftermarket ECU that can be tuned to meet your modifications. Also has your engine been properly broken in since the rebuild? My engine idled better after the break in period.

While his engine will run better after some break in time. It shouldn't be running this badly either. There is def a prob in there somewhere

Im beginning to really lean towards hte ISC as the culprit. I can get this thing to idle almost perfectly using just the slightest of bouncing my hand on the acc Cable. That makes me think that the ISC isnt operating because isn't it capable of rapid opening and closing far beyond what my hand can do?

By the way, Thanks guys for your assistance with this. I really love this car and it's been awaiting the day I can put her back on the road for over 4years now!I am eager beyond words to get her done!!!

allright, I think I need to start from scratch. What are the parts involved with controlling the engine idle and how does each of them work. I know that the air bleed screw allows a certain amount of air to bypass the butterfly, which allows the engine to get just the required amount for idle. Waht is the feedback device? What tells the ISC to open and for how long and how quickly, etc? Since the idle should be unaffected by a completely closed butterfly, there must be other pieces involved independent of the butterfly adjustments. So what is the device that controls the ISC or even better; because I assume the ISC gets it's direction from the ECU. What tells the ecu how much air to add or when it's about to stall?

While your ics could be bad and contribute to a poor idle. this is not your problem. Your car will still run without the ics. The stock computer uses o2 feedback, the ics and ignition timing to keep the idle steady. The ics only allows additional air into the engine to compinsate for load changes. Set the idle at the primary butterfly to allow more air in. Set the air bleed screw half a turn out. Set the idle to like 2000 if need be. You should not have to open and close the throttle like you're doing for the car to idle and run. Even with the ics unplugged the most you will have is irratic idle fluctuations.

ok guy's I've tried just about everything and I'm gonna blame this issue on the TPS. Heres my logic. The car starts up repeatdly without issue. To keep her running,I have to bounce my finger on the throttle cable, barely making any movement at all. The only thing connected to that mechanism is the TPS. Plus, when I hooked my multimeter up to the wires 3F and 3G, i couldnt seem to get 3G(the lower wire a.k.a. full range ) into range. That leads me to believe that something inside the sensor has gone bad. The FSM specifies between 0.1 -0.7 at the full range wire but the numbers I get don't even come close, I have to deduct that the sensor is bad.

has anyone done any kind of TPS bypass mod. I want to try see if theres a way to give the ECU the correct ranges despite the sensor to see if she idles. Just to verify that it is the TPS. we all know there not cheap!!

Hey guy's I still need your help. The bottom wire is reading 0.35 volts when it's should reading 0.01 to 0.07. That has to mean the sensor is the issue. no mater how I adjust the sensor i can't get the reading below that. I was thinking of splicing a resistor inline with the bottom wire to make it the correct voltage but not sure if I should. I just want to see if I gave the ecu the right voltage range, if that would solve the problem. Also not sure what ohm resistor to use but what do you think???

You must have read wrong the black wire which is full range or vta1 should be between 0.1 -0.7 when closed. The green and red wire which is narrow range or vta2 is 0.75 - 1.25 when closed. If you are getting these voltages your tps is fine.

Don't splice any resistors.

Your TPS might be installed wrong, it might have been removed to bypass the thermowax valve in the throttle body. There are little black plastic "feet" that can be installed in front of or behind the metal plate. If yours are installed wrong, your TPS voltage will be wrong and won't move correctly when you press the throttle.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/tps-adjustment-check-engine-light-help-777317/

I put the wrong readings in my earlier post by accident. 0.75 - 1.25 is what i was getting for the top wire. but I've checked and double checked the readings because I couldn't believe I was getting those readings. The green/red (second from top) wire, I can get into range but no matter where is position the sensor, the bottom wire (black/green) wont go any lower than 0.35 volts with the plates fully closed. I backed out the adjmnt. screw all the way and held the fast idle cam fully away from the lever with a screwdriver. I also readjusted the air bleed screw out from fully closed by 1/2 a turn. I will remove it and try to reinstall the TPS correctly. Does anybody have the resistance readings for the pins on the TPS without any voltage going to it? I think that might be the best way to figure this out since I have to take it off anyway? By the way, those little black feet; do the move independently of one another or are they on a common cam? Never mind, I guess i'll find out!! Thanks guys!

Why do you want it lower then .35? you only need it lower then .7 which it sounds like you have accomplished. Unless your voltages don't go anywhere close to 5 volts with the throttle fully opened, it sounds like your tps is working as it should.

Because with the plates fully closed, the readings are supposed to be between 0.1 to 0.7 and I think thats the reason my motor keeps stalling. The ecu is getting conflicting readings and can't compensate. I could be wrong but I don't know. Its just one more thing to eliminate as the cause of my problem!!! If this isn't the cause of the issue then I'm stuck. I don't know what to do next!!!!

Yea .35 is between .1 and .7 I didn't look at it that way, i guess your right. I believe i was trying to get it down to .1. But what else could be the issue then, because the engine still stalls if i dont tap the cable?

Do I have to raise the fuel pressure because it's ported? Do I have to change the idle adjustments because it's ported? Do I have to increase backpressure for the same reason? What would happen if the timing pickups were reversed?

If the timing pickups were reversed it would run very badly. The fuel pressure is the the same for a ported engine. Do you have a fuel pressure guage? Did you say your exhaust is dumped at the downpipe right now? I'm using my cell right now and can't go look. For your idle i would set the primary butterfly open more and try to set the idle at like 2000 or so. One other thing you can try at your own risk is take a rag soaked in gas and put it against the butterfly opening, then start the car. this will tell you if youre having some kind of fuel issue. the engine should run until the fuel is all pulled out the rag. Did you do the suggestions i posted earlier in the thread you never posted any results if so.

I missed you suggestions but I'll go back and find them. Yea, I do have a fuel pressure gauge. It's reading 38 psi when I do the prime-jumper thing. The exhaust is dumped at the back of my high flow catted mid-pipe. I think I'm gonna risk the fuel soaked rag idea. I know it's dangerous but I'm desperate.